Not only was it a human skull, but it belonged to a Corellian man that knew Han Solo, and had been in the EU for a while. As pointed out by io9, Bidlo Kwerve was a Corellian Smuggler, who held the "great honor" of being the first meal for Jabba the Hutt's brand new pet rancor. But he was not lost to history during Disney's purge of the EU. In 2016, Bidlo Kwerve was mentioned in 2016's Star Wars: Complete Locations, so he was resurrected from Legends status, and is once again part of canon.